ignore test zk/etcd/consul in travis-ci.org

.travis.yml

@@ -2,7 +2,7 @@ language: go
 
 go:
   - 1.6.3
-  - 1.7.1
+  - 1.7.3
 
 notifications:
   email:

clientselector/ping_utils_test.go

@@ -3,11 +3,17 @@
 package clientselector
 
 import (
+	"log"
+	"os"
 	"strings"
 	"testing"
 )
 
 func TestPing(t *testing.T) {
+	if os.Getenv("travis") != "" {
+		log.Println("don't test this case in travis-ci.org")
+		return
+	}
 	hosts := []string{"www.163.com", "www.baidu.com", "www.qq.com", "www.taobao.com"}
 
 	for _, h := range hosts {